In general, he says, astronomy still pays too little attention to the polarization of light, often even trying to filter it out of or eliminate it from signals. "But it transmits information," Demory says. With his team, he is developing special instruments known as spectro-polarimeters that will one day enable researchers to detect signs of life even in space.
Operating in the blind
Surprisingly, polarimetric measurements also reveal differences between healthy and abnormal cells. This is probably due to the fact that the proliferating cells of a tumor crowd closely together – losing the optical properties of the tissue surrounding them. "We know that the polarisation of light is affected by the higher vascularisation and larger cell density of tumours,” Demory says. “What we do not yet know is how exactly the tissue structures shape the polarisation signal.”
At a symposium, Demory spoke with Raphael Sznitman, director of the ARTORG Center for Biomedical Engineering Research. Sznitman is an expert in machine learning and artificial intelligence. The two realized they could start a promising project by combining their expertise.
This is how BrainPol came into being, an interdisciplinary research project largely funded by the National Center of Competence in Research PlanetS. The project aims to master a medical challenge that has so far remained unsolved: Gliomas are malignant brain tumors. Approximately half of all patients die from them within a year. The greatest prospects for successful treatment result when the glioma can be detected early and cut out of the brain before it has spread metastases. "The problem is that the human eye cannot detect the early forms of glioma," Sznitman says. "Neurosurgeons have to operate in the blind, so to speak," Demory adds.
"We want to evaluate the polarimetric signals – and provide surgeons with them live during the operation to enhance their natural visual abilities with technology," says Sznitman. For their BrainPol project, the two researchers have called on specialists not only from neurosurgery, but also from the Institute of Pathology. There, experts examine the biopsies – and immediately send them to Demory's team, which then points the instruments for space search at the freshly removed brain cells.